US4394453A
Expired / Lapsed
US
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Envelopes for tungsten-halogen lamps
Assignee: Corning Glass Works
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Filing: 1981-09-08
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Granted: 1983-07-19
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Expires: 2001-09-08
Abstract
Abstract The present invention is directed to glasses especially suitable as envelopes for tungsten-halogen lamps. The glasses exhibit strain points of at least about 670 DEG C., a coefficient of thermal expansion (0 DEG -300 DEG C.) of 42-45x10-7/ DEG C. and can be readily melted and shaped utilizing conventional glass melting and high speed tube drawing processes. The glasses consist essentially, in weight percent, of -SiO2 60.0 +/- 1.5 -Al2O3 17.0 +/- 1.0 -B2O3 5.0 +/- 0.8 -CaO 11.4 +/- 0.8 -MgO 7.5 +/- 0.8 -
Inventors
- 👤 William H. Dumbaugh, Jr.
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 04:16
CPC Classifications
H; H01; H01K; H01K1/00; H01K1/28; C; C03; C03C; C03C3/00; C03C3/04; C03C3/076; C03C3/089; C03C3/091
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
120 words
A glass envelope for a tungsten-halogen incandescent lamp, said glass exhibiting a strain point of at least 670° C., a coefficient of thermal expansion (0°-300° C.) of 42-45×10 -7 /°C., a liquidus temperature below 1150° C., and a viscosity at the liquidus temperature greater than 2×10 4 poises, and consisting essentially, expressed in weight percent on the oxide basis, of ______________________________________
SiO.sub.2
60.0 ± 1.5
Al.sub.2 O.sub.3
17.0 ± 1.0
B.sub.2 O.sub.3
5.0 ± 0.8
CaO 11.4 ± 0.8
MgO 7.5 ± 0.8
______________________________________ the total Al 2 O 3 +SiO 2 being held between 74.5-78, the weight ratio SiO 2 :Al 2 O 3 being held between about 3.3-3.8, and the weight ratio CaO:MgO being held between about 1.3-1.8.
Claim 2
Dependent Claim
120 words
A glass envelope for a tungsten-halogen incandescent lamp, said glass exhibiting a strain point of at least 670° C., a coefficient of thermal expansion (0°-300° C.) of 42-45×10 -7 /°C., a liquidus temperature below 1150° C., and a viscosity at the liquidus temperature greater than 2×10 4 poises, and consisting essentially, expressed in weight percent on the oxide basis, of ______________________________________
SiO.sub.2
60.0 ± 1.5
Al.sub.2 O.sub.3
17.0 ± 1.0
B.sub.2 O.sub.3
5.0 ± 0.8
CaO 11.4 ± 0.8
MgO 7.5 ± 0.8
______________________________________ the total Al 2 O 3 +SiO 2 being held between 74.5-78, the weight ratio SiO 2 :Al 2 O 3 being held between about 3.3-3.8, and the weight ratio CaO:MgO being held between about 1.3-1.8.
Claim 3
Dependent Claim
33 words
A glass envelope according to claim 1 consisting essentially of ______________________________________
Al.sub.2 O.sub.3
17.4 ± 0.2
B.sub.2 O.sub.3
4.5 ± 0.1
CaO 10.9 ± 0.1
MgO 7.8 ± 0.1
SiO.sub.2 59.4 (remainder)
______________________________________
References Cited (Backward Citations)
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US4060423A
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| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1986-07-18 | 1987-01-17 | 1987-07-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-07-18 | 1991-01-17 | 1991-07-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-07-18 | 1995-01-17 | 1995-07-19 | $7700.00 | Window Closed / Lapsed |